Acquisition systems are based on lightweight 24-bit 5-channel GPS-synchronized recording units covering the frequency range from 0 to 50 kHz.
The data acquisition system has a receiver unit (Unit MT), two electromagnetic sensors, and four electrodes the placement of 4 electrodes arranged in a cross the disposition of the two orthogonal magnetic sensors at a distance of about 25 m from the instrument receiver.
The acquisition times are variable, but generally range from a minimum of 30 minutes to 12 hours for measuring point depending on the frequency bands set that we used for instrumentation, ranging from 1 Hz to 40 KHz.
Because data are acquired on a point (single sounding), to obtain a section is necessary to acquire more points along an alignment, with a spacing between points appropriate to the required resolution (normally between 50 and 100 m).
The contrast of resistivity provides an excellent tool for identifying geothermal targets.
The magnetotelluric surveys reach great depths in confined spaces.
To passive Tellurics MT, the conditions which cause difficult seismic energy propagation are largely irrelevant and so the method readily images the resistivity of the sub-surface.